Skip Wyona got it mostly right. Let me just add:
* Killing Apple Pay also killed Google Wallet. Both used NFC readers to interact with the smartphone. Neither platform has that option at either store right now.
* Apple Pay is very standardized, the same way that your electrical outlets are standardized. That's why Apple Pay worked on payment terminals that were originally installed (years ago) for Google Wallet. The only thing that makes it
Apple Pay is manner of storage of the credit information on the phones, and the software interaction that Apple does with the credit card stores.
The rest is based on a standard developed by
EMV Co. This same standard will be present on the next generation of your credit cards (assuming you're American) as they transition from Chip and Signature to Chip and Pin.
* The credit card companies pay Apple, not the stores you do business with. Your stores are already paying 2%-4% of each credit card transaction to the credit card companies. The credit card companies in turn are paying Apple .015% for every transaction done through Apple pay.
* CVS, Rite Aide, Walmart, Target, 7-11 and the rest are tired of paying that that two to four percent (or, billions annually) to the CC companies for credit card processing. Their rival digital wallet will not allow credit card transactions, only ACH transactions directly from your bank account.
Obviously, the credit card companies don't want to see that become popular, and that's why they're backing Apple and Googles digital wallets.
* Edit: Oh yes, and supposedly Apple Pay denies the merchants any data about the consumers, much different than they get from credit cards right now. Another reason for them to oppose Apple Pay, as it interferes with their data and market information gathering and use.